The latest idea is to launch on Thursday April 27th, which coincides with the letter W of the April Blogging from A to Z Challenge.
Jemima will be publishing details for the sign-up (to get a spot on the Giveaway) and BookLaunch Blast on her blog, with a special sign-up page with all the details and resources you need. She'll also be pushing it on her A to Z Theme Reveal post on 20th March. (link not active until then)
Watch here for full details, coming soon.